The evolution of native engineering at Tripadvisor: Part 1

Tripadvisor's iOS team was drowning in coordinator spaghetti. Navigation paths were impossible to trace, and even senior engineers couldn't debug their own flows.

Benoit Sarrazin shares how Tripadvisor migrated their large iOS team from MVVM-Coordinator to The Composable Architecture (TCA). This is part 1 of a 3-part series on modernizing their Server Driven UI platform.

Key Takeaways

• Navigation required 8 steps of duplicated events cascading through coordinator chains
• TCA migration reduced code volume by 15-30% while improving testability
• Leaf-to-root migration strategy kept the app functional throughout transition
• State mutators enabled shared logic across reducers without action duplication
• ObservableState macro delivered performance gains through granular property observation

The team discovered that testing difficulty became their best design feedback loop, revealing architectural problems before they shipped.